1. Field of the Invention
The present invention is directed to a valve cover locking screw assembly for a reciprocating pump.
2. Background of Invention
Drilling fluid (sometimes referred to as “drilling mud”), which is often times a petroleum or water based fluid product, is used in drilling and workover rig applications.
Drilling fluid serves a number of important functions in the drilling operations. The drilling fluid serves to assist in cleaning the bottom of the wellbore hole and transports drill cuttings to the surface where they are removed. The drilling fluid also cools the drill bit and lubricates the drill stem. Additionally, the drilling fluid assists in supporting the walls of the wellbore and discourages entry of fluids into the well. Finally, the drilling fluid can reveal the presence of oil, gas or water that may enter the fluid from a formation being drilled and may reveal information about the formation through drill cuttings.
The drilling fluid at a drilling or workover rig site is utilized in a circulating system so that the drilling fluid may be reused. In other words, the drilling fluid may be moved from the surface thousands of feet downhole and then returned to the surface. The time required for the drilling fluid to travel from pump suction to pump suction is known as a complete cycle.
A mud circulation system can include a mud tank. The mud tank can supply mud to a pump or pumps to begin circulation, receive the drilling fluid circulated out of the well and store reserve mud.
A reciprocating pump or pumps are utilized to move the drilling fluid from the surface through a series of pipes including a standpipe and rotary hose and then downhole to the subterranean drilling location. The drilling fluid will often be moved thousands of feet down drill pipe and out small nozzles in a drill bit. Thereafter, the pumps circulate the drilling fluid back to the surface through an annulus where the drilling mud is passed through various conditioning equipment. The equipment may include a vibrating screen assembly and separator mechanisms to remove entrained solids such as rocks or drilling cuttings. Other equipment may include degassers and mud agitators.
A reciprocating pump is a positive displacement pump. A plunger or piston reciprocates (moves back and forth) inside a cylinder. The reciprocating movement of the piston displaces or moves the drilling fluid. Drilling rigs have utilized both single-acting triplex pumps and double-acting duplex pumps.
Mud pumps are known to operate at up to 2200 horsepower. These mud pumps can include components which are required to be frequently changed and also inspected from time to time. For example, valves, seats, and springs are expendable items that may be inspected and replaced.
In one known mud pump arrangement, a module block contains a number of bores. A removable valve cover closes the bores and a valve cover locking ring surrounds each bore. A cylindrical locking screw having an open bottom and a closed top includes external threads which mate with internal threads on the locking ring. A number of openings perpendicular to the axis of the cylindrical walls is provided through the walls of the cylindrical screw so that a pole or other tool is placed through an opening or openings to gain leverage in order to tighten or untighten the screw.